Impact hammer crimping attachment



June 15, 1965 B. E. POGUE, JR., ET-AL 3,

IMPACT HAMMER CRIMPING ATTACHMENT 2 Sheets-Sheet 1 Filed Oct. 16, 1962 INVENTOR; BARNEY E- Poe-ug O- C. W\\ $ON, I2.

BY QXMW$MM ATTORNEYS June 15, 1965 B. E. POGUE, JR., ETAL 3,

IMPACT HAMMER CRIMPING ATTACHMENT 2 Sheets-Sheet 2 Filed Oct. 16, 1962 readily portable.

United States Patent IMPACT HAMMER CRIMPING ATTACHMENT Barney E. Pogue, Jr., and 0 C. Wilson, In, Shreveport,

La, assignors, by direct and mesne assignments of onehalf to Q. C. Wilson, .lr., Cadrlo Farrish, and one-half to William E. Dowden, Natchitoches Parrish, La.

Filed Oct. 16, 1962, Ser. No. 236,918 4 Claims. ((Il. 29-44358) This invention relates to a crimping tool, for bending the edges of sheet metal, and in particular, to an attachment for air hammers or the like, for providing the closing and sealing fold in a corner interlock in metal ducts, commonly known as the Pittsburgh lock. Present-day requirements in this field of operations are, of course, enormous in extent, and on-site closing operations for this type of metal work have long since outmoded the slow and laborious method, using an ordinary hammer. However, although special crimping tools have been proposed from time to time, these have not found acceptance to any noteworthy degree, for various reasons, such as unduly complex structure, high cost, and lack of versatility and adaptability.

It is therefore a general object of the invention to provide a crimping tool which is simple in structure, and Another object is to provide a tool which reduces to a minimum, the requirements for special skill in operation. More particularly, it is an object to provide a tool for progressive crimping of a corner fold, having inherent guiding and spacing features.

In still greater particular, it is an object to provide a reciprocating, crimping tool which, in addition to the advantageous appertaining to the foregoing objects, is capable of simple adjustment for multi-stage crimping operations, for dealing with less tractable materials. A related object is to provide a crimper which is adjustable in orientation.

Yet another object is to provide a tool as aforesaid,

which, in addition is capable of employment with a powerimpact tool, or manually delivered blows, as with a hammer, the guidance, precision and speed being supplied by the tool in either case.

Another object is to provide a reciprocating, crimping tool, having a mount which also functions as a back-up dolly.

It is also among the objects to provide a tool which is easy of manufacture, and low in cost.

These and other ends, which will be apparent, are attained by the present invention, a preferred form of which is described in the following specification, as illustrated in the drawings, in which:

FIGURE 1 is a perspective view of a tool, according to v the invention, applied to the interlocking corner of a sheetmetal duct, in the course of the first stage of a two-stage crimping operation,

FIGURE 2 is a perspective view of the corner of a duct having the interlocking fold, showing the completion of the first stage of crimping indicated as in progress in FIGURE 1,

FIGURE 3 is a perspective view of the tool in the course of applying the second, and final, stage of crimping,

FIGURE 4 is a view similar to FIGURE 2, showing the completionof the second, and final, stage of crimping, shown in progress in FIGURE 3,

FIGURE 5 is a front elevational view of the tool, as seen from the right of FIGURE 1,

FIGURE 6 is a vertical section through the middle of the tool, taken on the plane of the line 66 of FIGURE 5,

FIGURE '7 is a view similar to FIGURE 6, with the tool parts adjusted to the relative positions shown in FIG- URE 3, and

3,188,729 Patented June 15, 1965 FIGURE 8 is a sectional view taken on the line 8--8 of FIGURE 7.

Referring to the drawings by characters of reference, there is shown, in FIGURE 1, a fragment of rectangular, sheet-metal conduit, with a side wall 10, having an S fold 12, with a flattened, inner loop 14, and an outer loop 16, with its outer side extending above the bight at the top of loop 14, and spaced therefrom to define a channel having a width about equal to the thickness of the metal. The top wall 18 is bent at right angles near its free edge, producing a depending skirt 2%, which nests in the said groove of the S fold, in the closed position of the conduit, and the assembly is sealed by bending, or crimping, the upper portion of outer loop 16, to the position shown in FIGURE 4. This corner interlock is known as the Pittsburgh lock, and it is a prime purpose of the inventon to facilitate the folding, or crimping operation involved.

The crimping tool, in the preferred embodiment illustrated, comprises a main body, or block 22, which serves the plural functions of providing a mount for the impact ing hammer, or ram, of guiding the progress of the tool in an operative path, along the work, and of serving as a back-up dolly. To these ends, the block 22 is relatively massive, and has at least one fiat face 24, on its inner side, for planar engagement with the outer surface of conduit side wall 10. Conveniently, the block 22 is of uniform thickness, so that its outer face is also planar, and, as shown, the height and width are roughly comparable, with the height somewhat greater. For holding it steady against the work, the block carries a handle 26, threadedly secured in the block, and extending from its outer face. The block also has a U-form notch 28, medially of its upper edge, providing clearance for the swingable, reciprocable, impact unit, presently to be described.

Block 22 has a further, spacing and guide means, positioning it relatively to top wall 18, comprising a angle member, having end tabs 30, secured by welding to the top of the block, on opposite sides of notch 28, and a depending skirt 32, adapted to contact top wall 18 of the conduit, and thus space the block 22 with respect to the plane of top wall 18. In particular, the height of skirt 32 is such that the tabs 30 clear the top edge of the S section 16, prior to folding. Also the skirt 32 is spaced from block 22 at a distance sufiicient to accommodate the portion to be folded over. Preferably this spacing is substantially equal to the width of the folded portion, so that the skirt forms a positive guide means during crimping, by engaging the edge of the folded portion, and thus holding the block against the work. Between the tabs 30, skirt 32 has a U-shaped notch 34, medially of its length, which assists in observation of progress of the work, and also provides clearance for the reciprocating hammer unit, as required.

The hammer unit comprises a cylindrical rod 36, slidably mounted in a sleeve, or cylinder 38, which is swingably mounted on block 22 by means of a bail-like arrangement comprising a pair of curvate struts 40, with upper ends welded, or otherwise secured, to opposite sides of sleeve 38, near the top thereof, and having inturned, bent, lower ends 42, of circular cross section, received in suitable bores in the respective, side edges of block 22, and constituting trunnions, for the swinging movement of the hammer unit, as a whole.

Rod 36, which forms the reciprocating hammer element providing the impacts for the work, has a lower, mushroom type head 44, which is the contact element in impacting the work, and which also limits upward movement of rod 36 in sleeve 38. The rod 36 is normally held in its extreme upper position, with head 44 in contact with the bottom edge of sleeve 38, by means of a compression, coil spring 46, surrounding rod 36, with its lower end abutting the top edge of sleeve 38, and its upper end contacting a washer 48, the latter held against upward movement by a 3 split, spring ring retainer 50', carried in an annular groove in rod 36, in a reduced end 52 of the rod, at the shoulder formed thereby. Thus, the rod, or hammering ram, 36 may be moved downward, against the bias of spring 46, in response to an impacting force, which may be applied by an air or electrical impact hammer having an adaptor with a'cavity adapted to receive the reduced end 52, such as the collet 54 shown in dash lines in FIGURES 1 and 3.. Obviously, the ram will be of suitable hardness, at least at the ends; to withstand the rough usage.

As seen in FIGURES 6 and 7, the struts 40 are arranged at a small, oblique angle to. the axis of the hammer unit,

for proper mechanical advantage in the crimping opera tions, as will be seen. a

For the first stage of the two-stage crimping operation, the back-up dolly and mounting block'22 is appliedto'the side wall 10, with skirt 32 dwelling on top wall 18, and the hammer unit is swungton its trunnions to about the position shown in FIGURE 6-. The exact angular position is not critical, and the operator will soon determine the most favorable angle applicable to his own technique. Also, it

-is possible to vary the angle of the hammer during the progress of the initial bending stage. However, it is most expedient to select an angle and maintain it throughout the first stage, so that progressalong the line of crimping is uninterrupted. Experience has shown that an angle which produces a fold of about 45 in the first stage is tobe tangular block, with parallel faces, and of constant thickness, having a U-form notch in its top edge, and a handle ext-endingperpendicularly from one of said faces, a hookform guide element of right-angular form in cross section, with one flange secured to said top edge of said block and extending perpendicularly from the inner face of said block, on the side opposite said handle, and having a notch coextensive in width with-thenotch in the block, and the other flange parallel to said inner face of said block,

spaced theref rom, and having a notch communicating with the notchin said one flange, coextensive in width therewith, and terminating medially of the depth of said other flange, a cylindrical sleeve, a pair of supporting struts secured t-o'said sleeve at diametrically opposite locations thereon, near the upper end thereof, arranged in a plane at'an oblique angle to theaxis of said sleeve, and having inturned lower ends of circular cross section, journalled in opposite side edges of said'block, a reciprocating .rod

'pivota'lly mounted for sliding movement in said sleeve and longitudinally-extending in alignment with the notch in said block, said rod having inner and outer end portions 7 extending beyond the respective ends of said sleeve, a head on the inner portion of said rod and located below the adjacent end of said sleeve, a coil spring surrounding the outer end portion of said rod, detent means on the outer end portion of said sleeve engageable by said spring to urge said head against said sleeve, and a reduced upper end on the outer end portion of said rod,for receiving the output end of a reciprocating power tool.

2. A crimping tool for folding the edges of sheet metal,

comprising a generally rectangular block, with parallel along the work, with the first position showing contact a with the work, and before any folding occurs, and the second position showing the element 16, inbroken lines, forced into the 45 folded condition. It should be understood that this operation, although involving a plurality of impacts, is almost instantaneous, so that the tool is slowly, but continuously'moved along the lineof work,

The 45 folded condition of element 16 is shown in full lines, in FIGURE 7, and here, the hammer unit is shown as swung into a substantially vertical position, for a second surface of top wall 18. Here, it will be noted that the angular disposition of struts 40, with respect to the axis ofv the hammer unit, compensates for the offset location of run along the work to complete the seal by further folding element 16 into 90 disposition, and contact with the outer stage position of the hammer, its exact orientation is not 1 7 critical, and the opening 34 in the skirt 32 will'provide some clearance for a degree of obliquity in the hammer system, if, such be deemed necessary or desirable.

,As stated; above, the block 22 serves, among other things, as a back-up dolly, and in the closed systempof block and reciprocating hammer, the ultimate thrust of the .While a certain preferredembodimentthas been shown the spirit and scope of the'appende d claims.

We claimm 1 1. VA crimping tool for edge folding;of interlocking corners, in sheet metal work, comprisinga generally rec- 'hammeris absorbed 'by the block. As shown, the head144' of the hammer overlaps the block:somewhat in all positions of the hammer, and this overlap may be varied, for

faces, having a notch in its top edge, and a handle extending from one of said faces, a hook-form guide element ,comprising a pairof tabs secured to said top edge of said block, on opposite sides'ofsaid notch, perpendicular to said faces, and extending from said block on the side opposite said handle, a skirt depending from said'tabs, in

spaced relation to the other of said faces of said block,

parallel thereto, a sleeve, a pair of supporting struts secured to said sleeve atopposite locations thereon, near the upper end thereof, arranged in a plane at an oblique angle 'to said sleeve, and having inturned,'lowerends journalled in opposite side edges of said block, and positioning said 'sleeve' for registration with said notch in said block during swinging movement, a reciprocating rod pivotally mounted for sliding movement in said sleeve and longitudinally-extending in alignment with the notch in said block, said rod having inner and outer end portions extending beyond the respective ends ofsaid sleeve, a head on the inner end por- "tion of said rodand located below-thefadjacent end of said sleeve, a coil spring surrounding the outer end portion of said'rod, and detent means on the oute'rend portion of said rod engageable by said spring to urge said head against said sleeve 3. A tool for folding edges of sheet metal comprising a block having a plane face and a notch in one edge, a hook 'member carried by said one edge,:on opposite sides of said notch and having askirt-portion parallel to, and spaced from, saidplane face, with a free edge terminating substantially opposite the innermost portion ofrsaid notch, and a sleeve carried by said block and having'a reciprocable, in'ner rod, said sleevemounted for swingi ng move- ,viously, it istalso possible to operate with the use of an I ordinary hammer to furnish theimp'acts, in which case it would be'desirable to provide the end 52 of the hammer. 'unit with a replaceable head, or provide a rod which is specially hardened, to resist random wear or deformation.

and described, modifications will be-apparenhin' the light of this disclosure, and the invention should not, therefore, 7

be deemed'as limited, exceptlinsofar as shall appear from ment in a planetransversetto said plane face and passing being pivotally mounted for; sliding movement in said vsleeve and longitudinally-extending in alignmentwith the notch'in said block,fand having inner and outer end porttionst'extending beyond the respective ends of said sleeve,

said sleeve being arranged with its axis at an angle to its 'radius "of swing. t 1 a V A 4. A toolfor folding edges of. sheet metal comprising ablock having a plane face andia notchin one edge, a

,hook member carried by said one edge, on opposite sides of sai-d notch and having a skirt portion parallel to, and

spaced from, said plane face, with a free edge terminating References Cited by the Examiner substantially opposite the innermost portion of said notch, UNITED STATES PATENTS and a sleeve carried by said block and having a reciprocable, inner rod, said sleeve mounted with its axis in a 309,4? 12/84 Leher. 113 56 plane transverse to said plane face and passing through 5 893186 7/08 Nesmlthsaid notch, and the innermost end of said sleeve spaced 2,297,885 10/42 Graf et a1 X from said innermost portion of said notch, said rod being 2,655,825 10/53 Gendron 81-15 2,903,988 9/59 Engel et a1. 11357 pivotally mounted for sliding movement in said sleeve and longitudinally-extending in alignment with the notch in said block, and having inner and outer end portions ex- 10 tending beyond the respective ends of said sleeve.

WILLIAM FELDMAN, Primary Examiner. 

4. A TOOL FOR FOLDING EDGES OF SHEET METAL COMPRISING A BLOCK HAVING A PLANE FACE AND A NOTCH IN ONE EDGE, A HOOK MEMBER CARRIED BY ONE EDGE, ON OPPOSITE SIDES OF SAID NOTCH AND HAVING A SKIRT PORTION PARALLEL TO, AND SPACED FROM, SAID PLANE FACE, WITH A FREE EDGE TERMINATING SUBSTANTIALLY OPPOSITE THE INNERMOST PORTION OF SAID NOTCH, AND A SLEEVE CARRIED BY SAID BLOCK AND HAVING A RECIPROCABLE, INNER ROD, SAID SLEEVE MOUNTED WITH ITS AXIS IN A PLANE TRANSVERSE TO SAID PLANE FACE AND PASSING THROUGH SAID NOTCH, AND THE INNERMOST END OF SAID SLEEVE SPACED FROM SAID INNERMOST PORTION OF SAID NOTCH, SAID ROD BEING PIVOTALLY MOUNTED FOR SLIDING MOVEMENT IN SAID SLEEVE AND LONGITUDINALLY-EXTENDING IN ALIGNMENT WITH THE NOTCH IN SAID BLOCK, AND HAVING INNER AND OUTER END PORTIONS EXTENDING BEYOND THE RESPECTIVE ENDS OF SAID SLEEVE. 